drivers/soc/ixp4xx/ixp4xx-qmgr.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Intel IXP4xx Queue Manager driver for Linux
  *
  * Copyright (C) 2007 Krzysztof Halasa <khc@pm.waw.pl>
  */

 #include <linux/ioport.h>
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/soc/ixp4xx/qmgr.h>
 #include <mach/hardware.h>
 #include <linux/soc/ixp4xx/cpu.h>

 static struct qmgr_regs __iomem *qmgr_regs;
 static int qmgr_irq_1;
 static int qmgr_irq_2;
 static spinlock_t qmgr_lock;
 static u32 used_sram_bitmap[4]; /* 128 16-dword pages */
 static void (*irq_handlers[QUEUES])(void *pdev);
 static void *irq_pdevs[QUEUES];

 #if DEBUG_QMGR
 char qmgr_queue_descs[QUEUES][32];
 #endif

 void qmgr_put_entry(unsigned int queue, u32 val)
 {
 #if DEBUG_QMGR
 	BUG_ON(!qmgr_queue_descs[queue]); /* not yet requested */

 	printk(KERN_DEBUG "Queue %s(%i) put %X\n",
 	       qmgr_queue_descs[queue], queue, val);
 #endif
 	__raw_writel(val, &qmgr_regs->acc[queue][0]);
 }

 u32 qmgr_get_entry(unsigned int queue)
 {
 	u32 val;
 	val = __raw_readl(&qmgr_regs->acc[queue][0]);
 #if DEBUG_QMGR
 	BUG_ON(!qmgr_queue_descs[queue]); /* not yet requested */

 	printk(KERN_DEBUG "Queue %s(%i) get %X\n",
 	       qmgr_queue_descs[queue], queue, val);
 #endif
 	return val;
 }

 static int __qmgr_get_stat1(unsigned int queue)
 {
 	return (__raw_readl(&qmgr_regs->stat1[queue >> 3])
 		>> ((queue & 7) << 2)) & 0xF;
 }

 static int __qmgr_get_stat2(unsigned int queue)
 {
 	BUG_ON(queue >= HALF_QUEUES);
 	return (__raw_readl(&qmgr_regs->stat2[queue >> 4])
 		>> ((queue & 0xF) << 1)) & 0x3;
 }

 /**
  * qmgr_stat_empty() - checks if a hardware queue is empty
  * @queue:	queue number
  *
  * Returns non-zero value if the queue is empty.
  */
 int qmgr_stat_empty(unsigned int queue)
 {
 	BUG_ON(queue >= HALF_QUEUES);
 	return __qmgr_get_stat1(queue) & QUEUE_STAT1_EMPTY;
 }

 /**
  * qmgr_stat_below_low_watermark() - checks if a queue is below low watermark
  * @queue:	queue number
  *
  * Returns non-zero value if the queue is below low watermark.
  */
 int qmgr_stat_below_low_watermark(unsigned int queue)
 {
 	if (queue >= HALF_QUEUES)
 		return (__raw_readl(&qmgr_regs->statne_h) >>
 			(queue - HALF_QUEUES)) & 0x01;
 	return __qmgr_get_stat1(queue) & QUEUE_STAT1_NEARLY_EMPTY;
 }

 /**
  * qmgr_stat_full() - checks if a hardware queue is full
  * @queue:	queue number
  *
  * Returns non-zero value if the queue is full.
  */
 int qmgr_stat_full(unsigned int queue)
 {
 	if (queue >= HALF_QUEUES)
 		return (__raw_readl(&qmgr_regs->statf_h) >>
 			(queue - HALF_QUEUES)) & 0x01;
 	return __qmgr_get_stat1(queue) & QUEUE_STAT1_FULL;
 }

 /**
  * qmgr_stat_overflow() - checks if a hardware queue experienced overflow
  * @queue:	queue number
  *
  * Returns non-zero value if the queue experienced overflow.
  */
 int qmgr_stat_overflow(unsigned int queue)
 {
 	return __qmgr_get_stat2(queue) & QUEUE_STAT2_OVERFLOW;
 }

 void qmgr_set_irq(unsigned int queue, int src,
 		  void (*handler)(void *pdev), void *pdev)
 {
 	unsigned long flags;

 	spin_lock_irqsave(&qmgr_lock, flags);
 	if (queue < HALF_QUEUES) {
 		u32 __iomem *reg;
 		int bit;
 		BUG_ON(src > QUEUE_IRQ_SRC_NOT_FULL);
 		reg = &qmgr_regs->irqsrc[queue >> 3]; /* 8 queues per u32 */
 		bit = (queue % 8) * 4; /* 3 bits + 1 reserved bit per queue */
 		__raw_writel((__raw_readl(reg) & ~(7 << bit)) | (src << bit),
 			     reg);
 	} else
 		/* IRQ source for queues 32-63 is fixed */
 		BUG_ON(src != QUEUE_IRQ_SRC_NOT_NEARLY_EMPTY);

 	irq_handlers[queue] = handler;
 	irq_pdevs[queue] = pdev;
 	spin_unlock_irqrestore(&qmgr_lock, flags);
 }


 static irqreturn_t qmgr_irq1_a0(int irq, void *pdev)
 {
 	int i, ret = 0;
 	u32 en_bitmap, src, stat;

 	/* ACK - it may clear any bits so don't rely on it */
 	__raw_writel(0xFFFFFFFF, &qmgr_regs->irqstat[0]);

 	en_bitmap = qmgr_regs->irqen[0];
 	while (en_bitmap) {
 		i = __fls(en_bitmap); /* number of the last "low" queue */
 		en_bitmap &= ~BIT(i);
 		src = qmgr_regs->irqsrc[i >> 3];
 		stat = qmgr_regs->stat1[i >> 3];
 		if (src & 4) /* the IRQ condition is inverted */
 			stat = ~stat;
 		if (stat & BIT(src & 3)) {
 			irq_handlers[i](irq_pdevs[i]);
 			ret = IRQ_HANDLED;
 		}
 	}
 	return ret;
 }


 static irqreturn_t qmgr_irq2_a0(int irq, void *pdev)
 {
 	int i, ret = 0;
 	u32 req_bitmap;

 	/* ACK - it may clear any bits so don't rely on it */
 	__raw_writel(0xFFFFFFFF, &qmgr_regs->irqstat[1]);

 	req_bitmap = qmgr_regs->irqen[1] & qmgr_regs->statne_h;
 	while (req_bitmap) {
 		i = __fls(req_bitmap); /* number of the last "high" queue */
 		req_bitmap &= ~BIT(i);
 		irq_handlers[HALF_QUEUES + i](irq_pdevs[HALF_QUEUES + i]);
 		ret = IRQ_HANDLED;
 	}
 	return ret;
 }


 static irqreturn_t qmgr_irq(int irq, void *pdev)
 {
 	int i, half = (irq == qmgr_irq_1 ? 0 : 1);
 	u32 req_bitmap = __raw_readl(&qmgr_regs->irqstat[half]);

 	if (!req_bitmap)
 		return 0;
 	__raw_writel(req_bitmap, &qmgr_regs->irqstat[half]); /* ACK */

 	while (req_bitmap) {
 		i = __fls(req_bitmap); /* number of the last queue */
 		req_bitmap &= ~BIT(i);
 		i += half * HALF_QUEUES;
 		irq_handlers[i](irq_pdevs[i]);
 	}
 	return IRQ_HANDLED;
 }


 void qmgr_enable_irq(unsigned int queue)
 {
 	unsigned long flags;
 	int half = queue / 32;
 	u32 mask = 1 << (queue & (HALF_QUEUES - 1));

 	spin_lock_irqsave(&qmgr_lock, flags);
 	__raw_writel(__raw_readl(&qmgr_regs->irqen[half]) | mask,
 		     &qmgr_regs->irqen[half]);
 	spin_unlock_irqrestore(&qmgr_lock, flags);
 }

 void qmgr_disable_irq(unsigned int queue)
 {
 	unsigned long flags;
 	int half = queue / 32;
 	u32 mask = 1 << (queue & (HALF_QUEUES - 1));

 	spin_lock_irqsave(&qmgr_lock, flags);
 	__raw_writel(__raw_readl(&qmgr_regs->irqen[half]) & ~mask,
 		     &qmgr_regs->irqen[half]);
 	__raw_writel(mask, &qmgr_regs->irqstat[half]); /* clear */
 	spin_unlock_irqrestore(&qmgr_lock, flags);
 }

 static inline void shift_mask(u32 *mask)
 {
 	mask[3] = mask[3] << 1 | mask[2] >> 31;
 	mask[2] = mask[2] << 1 | mask[1] >> 31;
 	mask[1] = mask[1] << 1 | mask[0] >> 31;
 	mask[0] <<= 1;
 }

 #if DEBUG_QMGR
 int qmgr_request_queue(unsigned int queue, unsigned int len /* dwords */,
 		       unsigned int nearly_empty_watermark,
 		       unsigned int nearly_full_watermark,
 		       const char *desc_format, const char* name)
 #else
 int __qmgr_request_queue(unsigned int queue, unsigned int len /* dwords */,
 			 unsigned int nearly_empty_watermark,
 			 unsigned int nearly_full_watermark)
 #endif
 {
 	u32 cfg, addr = 0, mask[4]; /* in 16-dwords */
 	int err;

 	BUG_ON(queue >= QUEUES);

 	if ((nearly_empty_watermark | nearly_full_watermark) & ~7)
 		return -EINVAL;

 	switch (len) {
 	case  16:
 		cfg = 0 << 24;
 		mask[0] = 0x1;
 		break;
 	case  32:
 		cfg = 1 << 24;
 		mask[0] = 0x3;
 		break;
 	case  64:
 		cfg = 2 << 24;
 		mask[0] = 0xF;
 		break;
 	case 128:
 		cfg = 3 << 24;
 		mask[0] = 0xFF;
 		break;
 	default:
 		return -EINVAL;
 	}

 	cfg |= nearly_empty_watermark << 26;
 	cfg |= nearly_full_watermark << 29;
 	len /= 16;		/* in 16-dwords: 1, 2, 4 or 8 */
 	mask[1] = mask[2] = mask[3] = 0;

 	if (!try_module_get(THIS_MODULE))
 		return -ENODEV;

 	spin_lock_irq(&qmgr_lock);
 	if (__raw_readl(&qmgr_regs->sram[queue])) {
 		err = -EBUSY;
 		goto err;
 	}

 	while (1) {
 		if (!(used_sram_bitmap[0] & mask[0]) &&
 		    !(used_sram_bitmap[1] & mask[1]) &&
 		    !(used_sram_bitmap[2] & mask[2]) &&
 		    !(used_sram_bitmap[3] & mask[3]))
 			break; /* found free space */

 		addr++;
 		shift_mask(mask);
 		if (addr + len > ARRAY_SIZE(qmgr_regs->sram)) {
 			printk(KERN_ERR "qmgr: no free SRAM space for"
 			       " queue %i\n", queue);
 			err = -ENOMEM;
 			goto err;
 		}
 	}

 	used_sram_bitmap[0] |= mask[0];
 	used_sram_bitmap[1] |= mask[1];
 	used_sram_bitmap[2] |= mask[2];
 	used_sram_bitmap[3] |= mask[3];
 	__raw_writel(cfg | (addr << 14), &qmgr_regs->sram[queue]);
 #if DEBUG_QMGR
 	snprintf(qmgr_queue_descs[queue], sizeof(qmgr_queue_descs[0]),
 		 desc_format, name);
 	printk(KERN_DEBUG "qmgr: requested queue %s(%i) addr = 0x%02X\n",
 	       qmgr_queue_descs[queue], queue, addr);
 #endif
 	spin_unlock_irq(&qmgr_lock);
 	return 0;

 err:
 	spin_unlock_irq(&qmgr_lock);
 	module_put(THIS_MODULE);
 	return err;
 }

 void qmgr_release_queue(unsigned int queue)
 {
 	u32 cfg, addr, mask[4];

 	BUG_ON(queue >= QUEUES); /* not in valid range */

 	spin_lock_irq(&qmgr_lock);
 	cfg = __raw_readl(&qmgr_regs->sram[queue]);
 	addr = (cfg >> 14) & 0xFF;

 	BUG_ON(!addr);		/* not requested */

 	switch ((cfg >> 24) & 3) {
 	case 0: mask[0] = 0x1; break;
 	case 1: mask[0] = 0x3; break;
 	case 2: mask[0] = 0xF; break;
 	case 3: mask[0] = 0xFF; break;
 	}

 	mask[1] = mask[2] = mask[3] = 0;

 	while (addr--)
 		shift_mask(mask);

 #if DEBUG_QMGR
 	printk(KERN_DEBUG "qmgr: releasing queue %s(%i)\n",
 	       qmgr_queue_descs[queue], queue);
 	qmgr_queue_descs[queue][0] = '\x0';
 #endif

 	while ((addr = qmgr_get_entry(queue)))
 		printk(KERN_ERR "qmgr: released queue %i not empty: 0x%08X\n",
 		       queue, addr);

 	__raw_writel(0, &qmgr_regs->sram[queue]);

 	used_sram_bitmap[0] &= ~mask[0];
 	used_sram_bitmap[1] &= ~mask[1];
 	used_sram_bitmap[2] &= ~mask[2];
 	used_sram_bitmap[3] &= ~mask[3];
 	irq_handlers[queue] = NULL; /* catch IRQ bugs */
 	spin_unlock_irq(&qmgr_lock);

 	module_put(THIS_MODULE);
 }

 static int ixp4xx_qmgr_probe(struct platform_device *pdev)
 {
 	int i, err;
 	irq_handler_t handler1, handler2;
 	struct device *dev = &pdev->dev;
 	struct resource *res;
 	int irq1, irq2;

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!res)
 		return -ENODEV;
 	qmgr_regs = devm_ioremap_resource(dev, res);
 	if (IS_ERR(qmgr_regs))
 		return PTR_ERR(qmgr_regs);

 	irq1 = platform_get_irq(pdev, 0);
 	if (irq1 <= 0)
 		return irq1 ? irq1 : -EINVAL;
 	qmgr_irq_1 = irq1;
 	irq2 = platform_get_irq(pdev, 1);
 	if (irq2 <= 0)
 		return irq2 ? irq2 : -EINVAL;
 	qmgr_irq_2 = irq2;

 	/* reset qmgr registers */
 	for (i = 0; i < 4; i++) {
 		__raw_writel(0x33333333, &qmgr_regs->stat1[i]);
 		__raw_writel(0, &qmgr_regs->irqsrc[i]);
 	}
 	for (i = 0; i < 2; i++) {
 		__raw_writel(0, &qmgr_regs->stat2[i]);
 		__raw_writel(0xFFFFFFFF, &qmgr_regs->irqstat[i]); /* clear */
 		__raw_writel(0, &qmgr_regs->irqen[i]);
 	}

 	__raw_writel(0xFFFFFFFF, &qmgr_regs->statne_h);
 	__raw_writel(0, &qmgr_regs->statf_h);

 	for (i = 0; i < QUEUES; i++)
 		__raw_writel(0, &qmgr_regs->sram[i]);

 	if (cpu_is_ixp42x_rev_a0()) {
 		handler1 = qmgr_irq1_a0;
 		handler2 = qmgr_irq2_a0;
 	} else
 		handler1 = handler2 = qmgr_irq;

 	err = devm_request_irq(dev, irq1, handler1, 0, "IXP4xx Queue Manager",
 			       NULL);
 	if (err) {
 		dev_err(dev, "failed to request IRQ%i (%i)\n",
 			irq1, err);
 		return err;
 	}

 	err = devm_request_irq(dev, irq2, handler2, 0, "IXP4xx Queue Manager",
 			       NULL);
 	if (err) {
 		dev_err(dev, "failed to request IRQ%i (%i)\n",
 			irq2, err);
 		return err;
 	}

 	used_sram_bitmap[0] = 0xF; /* 4 first pages reserved for config */
 	spin_lock_init(&qmgr_lock);

 	dev_info(dev, "IXP4xx Queue Manager initialized.\n");
 	return 0;
 }

 static int ixp4xx_qmgr_remove(struct platform_device *pdev)
 {
 	synchronize_irq(qmgr_irq_1);
 	synchronize_irq(qmgr_irq_2);
 	return 0;
 }

 static const struct of_device_id ixp4xx_qmgr_of_match[] = {
 	{
 		.compatible = "intel,ixp4xx-ahb-queue-manager",
         },
 	{},
 };

 static struct platform_driver ixp4xx_qmgr_driver = {
 	.driver = {
 		.name           = "ixp4xx-qmgr",
 		.of_match_table = of_match_ptr(ixp4xx_qmgr_of_match),
 	},
 	.probe = ixp4xx_qmgr_probe,
 	.remove = ixp4xx_qmgr_remove,
 };
 module_platform_driver(ixp4xx_qmgr_driver);

 MODULE_LICENSE("GPL v2");
 MODULE_AUTHOR("Krzysztof Halasa");

 EXPORT_SYMBOL(qmgr_put_entry);
 EXPORT_SYMBOL(qmgr_get_entry);
 EXPORT_SYMBOL(qmgr_stat_empty);
 EXPORT_SYMBOL(qmgr_stat_below_low_watermark);
 EXPORT_SYMBOL(qmgr_stat_full);
 EXPORT_SYMBOL(qmgr_stat_overflow);
 EXPORT_SYMBOL(qmgr_set_irq);
 EXPORT_SYMBOL(qmgr_enable_irq);
 EXPORT_SYMBOL(qmgr_disable_irq);
 #if DEBUG_QMGR
 EXPORT_SYMBOL(qmgr_queue_descs);
 EXPORT_SYMBOL(qmgr_request_queue);
 #else
 EXPORT_SYMBOL(__qmgr_request_queue);
 #endif
 EXPORT_SYMBOL(qmgr_release_queue);
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Intel IXP4xx Queue Manager driver for Linux
	*
	* Copyright (C) 2007 Krzysztof Halasa <khc@pm.waw.pl>
	*/

	#include <linux/ioport.h>
	#include <linux/interrupt.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/platform_device.h>
	#include <linux/soc/ixp4xx/qmgr.h>
	#include <mach/hardware.h>
	#include <linux/soc/ixp4xx/cpu.h>

	static struct qmgr_regs __iomem *qmgr_regs;
	static int qmgr_irq_1;
	static int qmgr_irq_2;
	static spinlock_t qmgr_lock;
	static u32 used_sram_bitmap[4]; /* 128 16-dword pages */
	static void (irq_handlers[QUEUES])(void pdev);
	static void *irq_pdevs[QUEUES];

	#if DEBUG_QMGR
	char qmgr_queue_descs[QUEUES][32];
	#endif

	void qmgr_put_entry(unsigned int queue, u32 val)
	{
	#if DEBUG_QMGR
	BUG_ON(!qmgr_queue_descs[queue]); /* not yet requested */

	printk(KERN_DEBUG "Queue %s(%i) put %X\n",
	qmgr_queue_descs[queue], queue, val);
	#endif
	__raw_writel(val, &qmgr_regs->acc[queue][0]);
	}

	u32 qmgr_get_entry(unsigned int queue)
	{
	u32 val;
	val = __raw_readl(&qmgr_regs->acc[queue][0]);
	#if DEBUG_QMGR
	BUG_ON(!qmgr_queue_descs[queue]); /* not yet requested */

	printk(KERN_DEBUG "Queue %s(%i) get %X\n",
	qmgr_queue_descs[queue], queue, val);
	#endif
	return val;
	}

	static int __qmgr_get_stat1(unsigned int queue)
	{
	return (__raw_readl(&qmgr_regs->stat1[queue >> 3])
	>> ((queue & 7) << 2)) & 0xF;
	}

	static int __qmgr_get_stat2(unsigned int queue)
	{
	BUG_ON(queue >= HALF_QUEUES);
	return (__raw_readl(&qmgr_regs->stat2[queue >> 4])
	>> ((queue & 0xF) << 1)) & 0x3;
	}

	/**
	* qmgr_stat_empty() - checks if a hardware queue is empty
	* @queue: queue number
	*
	* Returns non-zero value if the queue is empty.
	*/
	int qmgr_stat_empty(unsigned int queue)
	{
	BUG_ON(queue >= HALF_QUEUES);
	return __qmgr_get_stat1(queue) & QUEUE_STAT1_EMPTY;
	}

	/**
	* qmgr_stat_below_low_watermark() - checks if a queue is below low watermark
	* @queue: queue number
	*
	* Returns non-zero value if the queue is below low watermark.
	*/
	int qmgr_stat_below_low_watermark(unsigned int queue)
	{
	if (queue >= HALF_QUEUES)
	return (__raw_readl(&qmgr_regs->statne_h) >>
	(queue - HALF_QUEUES)) & 0x01;
	return __qmgr_get_stat1(queue) & QUEUE_STAT1_NEARLY_EMPTY;
	}

	/**
	* qmgr_stat_full() - checks if a hardware queue is full
	* @queue: queue number
	*
	* Returns non-zero value if the queue is full.
	*/
	int qmgr_stat_full(unsigned int queue)
	{
	if (queue >= HALF_QUEUES)
	return (__raw_readl(&qmgr_regs->statf_h) >>
	(queue - HALF_QUEUES)) & 0x01;
	return __qmgr_get_stat1(queue) & QUEUE_STAT1_FULL;
	}

	/**
	* qmgr_stat_overflow() - checks if a hardware queue experienced overflow
	* @queue: queue number
	*
	* Returns non-zero value if the queue experienced overflow.
	*/
	int qmgr_stat_overflow(unsigned int queue)
	{
	return __qmgr_get_stat2(queue) & QUEUE_STAT2_OVERFLOW;
	}

	void qmgr_set_irq(unsigned int queue, int src,
	void (handler)(void pdev), void *pdev)
	{
	unsigned long flags;

	spin_lock_irqsave(&qmgr_lock, flags);
	if (queue < HALF_QUEUES) {
	u32 __iomem *reg;
	int bit;
	BUG_ON(src > QUEUE_IRQ_SRC_NOT_FULL);
	reg = &qmgr_regs->irqsrc[queue >> 3]; /* 8 queues per u32 */
	bit = (queue % 8) * 4; /* 3 bits + 1 reserved bit per queue */
	__raw_writel((__raw_readl(reg) & ~(7 << bit)) \| (src << bit),
	reg);
	} else
	/* IRQ source for queues 32-63 is fixed */
	BUG_ON(src != QUEUE_IRQ_SRC_NOT_NEARLY_EMPTY);

	irq_handlers[queue] = handler;
	irq_pdevs[queue] = pdev;
	spin_unlock_irqrestore(&qmgr_lock, flags);
	}


	static irqreturn_t qmgr_irq1_a0(int irq, void *pdev)
	{
	int i, ret = 0;
	u32 en_bitmap, src, stat;

	/* ACK - it may clear any bits so don't rely on it */
	__raw_writel(0xFFFFFFFF, &qmgr_regs->irqstat[0]);

	en_bitmap = qmgr_regs->irqen[0];
	while (en_bitmap) {
	i = __fls(en_bitmap); /* number of the last "low" queue */
	en_bitmap &= ~BIT(i);
	src = qmgr_regs->irqsrc[i >> 3];
	stat = qmgr_regs->stat1[i >> 3];
	if (src & 4) /* the IRQ condition is inverted */
	stat = ~stat;
	if (stat & BIT(src & 3)) {
	irq_handlers[i](irq_pdevs[i]);
	ret = IRQ_HANDLED;
	}
	}
	return ret;
	}


	static irqreturn_t qmgr_irq2_a0(int irq, void *pdev)
	{
	int i, ret = 0;
	u32 req_bitmap;

	/* ACK - it may clear any bits so don't rely on it */
	__raw_writel(0xFFFFFFFF, &qmgr_regs->irqstat[1]);

	req_bitmap = qmgr_regs->irqen[1] & qmgr_regs->statne_h;
	while (req_bitmap) {
	i = __fls(req_bitmap); /* number of the last "high" queue */
	req_bitmap &= ~BIT(i);
	irq_handlers[HALF_QUEUES + i](irq_pdevs[HALF_QUEUES + i]);
	ret = IRQ_HANDLED;
	}
	return ret;
	}


	static irqreturn_t qmgr_irq(int irq, void *pdev)
	{
	int i, half = (irq == qmgr_irq_1 ? 0 : 1);
	u32 req_bitmap = __raw_readl(&qmgr_regs->irqstat[half]);

	if (!req_bitmap)
	return 0;
	__raw_writel(req_bitmap, &qmgr_regs->irqstat[half]); /* ACK */

	while (req_bitmap) {
	i = __fls(req_bitmap); /* number of the last queue */
	req_bitmap &= ~BIT(i);
	i += half * HALF_QUEUES;
	irq_handlers[i](irq_pdevs[i]);
	}
	return IRQ_HANDLED;
	}


	void qmgr_enable_irq(unsigned int queue)
	{
	unsigned long flags;
	int half = queue / 32;
	u32 mask = 1 << (queue & (HALF_QUEUES - 1));

	spin_lock_irqsave(&qmgr_lock, flags);
	__raw_writel(__raw_readl(&qmgr_regs->irqen[half]) \| mask,
	&qmgr_regs->irqen[half]);
	spin_unlock_irqrestore(&qmgr_lock, flags);
	}

	void qmgr_disable_irq(unsigned int queue)
	{
	unsigned long flags;
	int half = queue / 32;
	u32 mask = 1 << (queue & (HALF_QUEUES - 1));

	spin_lock_irqsave(&qmgr_lock, flags);
	__raw_writel(__raw_readl(&qmgr_regs->irqen[half]) & ~mask,
	&qmgr_regs->irqen[half]);
	__raw_writel(mask, &qmgr_regs->irqstat[half]); /* clear */
	spin_unlock_irqrestore(&qmgr_lock, flags);
	}

	static inline void shift_mask(u32 *mask)
	{
	mask[3] = mask[3] << 1 \| mask[2] >> 31;
	mask[2] = mask[2] << 1 \| mask[1] >> 31;
	mask[1] = mask[1] << 1 \| mask[0] >> 31;
	mask[0] <<= 1;
	}

	#if DEBUG_QMGR
	int qmgr_request_queue(unsigned int queue, unsigned int len /* dwords */,
	unsigned int nearly_empty_watermark,
	unsigned int nearly_full_watermark,
	const char desc_format, const char name)
	#else
	int __qmgr_request_queue(unsigned int queue, unsigned int len /* dwords */,
	unsigned int nearly_empty_watermark,
	unsigned int nearly_full_watermark)
	#endif
	{
	u32 cfg, addr = 0, mask[4]; /* in 16-dwords */
	int err;

	BUG_ON(queue >= QUEUES);

	if ((nearly_empty_watermark \| nearly_full_watermark) & ~7)
	return -EINVAL;

	switch (len) {
	case 16:
	cfg = 0 << 24;
	mask[0] = 0x1;
	break;
	case 32:
	cfg = 1 << 24;
	mask[0] = 0x3;
	break;
	case 64:
	cfg = 2 << 24;
	mask[0] = 0xF;
	break;
	case 128:
	cfg = 3 << 24;
	mask[0] = 0xFF;
	break;
	default:
	return -EINVAL;
	}

	cfg \|= nearly_empty_watermark << 26;
	cfg \|= nearly_full_watermark << 29;
	len /= 16; /* in 16-dwords: 1, 2, 4 or 8 */
	mask[1] = mask[2] = mask[3] = 0;

	if (!try_module_get(THIS_MODULE))
	return -ENODEV;

	spin_lock_irq(&qmgr_lock);
	if (__raw_readl(&qmgr_regs->sram[queue])) {
	err = -EBUSY;
	goto err;
	}

	while (1) {
	if (!(used_sram_bitmap[0] & mask[0]) &&
	!(used_sram_bitmap[1] & mask[1]) &&
	!(used_sram_bitmap[2] & mask[2]) &&
	!(used_sram_bitmap[3] & mask[3]))
	break; /* found free space */

	addr++;
	shift_mask(mask);
	if (addr + len > ARRAY_SIZE(qmgr_regs->sram)) {
	printk(KERN_ERR "qmgr: no free SRAM space for"
	" queue %i\n", queue);
	err = -ENOMEM;
	goto err;
	}
	}

	used_sram_bitmap[0] \|= mask[0];
	used_sram_bitmap[1] \|= mask[1];
	used_sram_bitmap[2] \|= mask[2];
	used_sram_bitmap[3] \|= mask[3];
	__raw_writel(cfg \| (addr << 14), &qmgr_regs->sram[queue]);
	#if DEBUG_QMGR
	snprintf(qmgr_queue_descs[queue], sizeof(qmgr_queue_descs[0]),
	desc_format, name);
	printk(KERN_DEBUG "qmgr: requested queue %s(%i) addr = 0x%02X\n",
	qmgr_queue_descs[queue], queue, addr);
	#endif
	spin_unlock_irq(&qmgr_lock);
	return 0;

	err:
	spin_unlock_irq(&qmgr_lock);
	module_put(THIS_MODULE);
	return err;
	}

	void qmgr_release_queue(unsigned int queue)
	{
	u32 cfg, addr, mask[4];

	BUG_ON(queue >= QUEUES); /* not in valid range */

	spin_lock_irq(&qmgr_lock);
	cfg = __raw_readl(&qmgr_regs->sram[queue]);
	addr = (cfg >> 14) & 0xFF;

	BUG_ON(!addr); /* not requested */

	switch ((cfg >> 24) & 3) {
	case 0: mask[0] = 0x1; break;
	case 1: mask[0] = 0x3; break;
	case 2: mask[0] = 0xF; break;
	case 3: mask[0] = 0xFF; break;
	}

	mask[1] = mask[2] = mask[3] = 0;

	while (addr--)
	shift_mask(mask);

	#if DEBUG_QMGR
	printk(KERN_DEBUG "qmgr: releasing queue %s(%i)\n",
	qmgr_queue_descs[queue], queue);
	qmgr_queue_descs[queue][0] = '\x0';
	#endif

	while ((addr = qmgr_get_entry(queue)))
	printk(KERN_ERR "qmgr: released queue %i not empty: 0x%08X\n",
	queue, addr);

	__raw_writel(0, &qmgr_regs->sram[queue]);

	used_sram_bitmap[0] &= ~mask[0];
	used_sram_bitmap[1] &= ~mask[1];
	used_sram_bitmap[2] &= ~mask[2];
	used_sram_bitmap[3] &= ~mask[3];
	irq_handlers[queue] = NULL; /* catch IRQ bugs */
	spin_unlock_irq(&qmgr_lock);

	module_put(THIS_MODULE);
	}

	static int ixp4xx_qmgr_probe(struct platform_device *pdev)
	{
	int i, err;
	irq_handler_t handler1, handler2;
	struct device *dev = &pdev->dev;
	struct resource *res;
	int irq1, irq2;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res)
	return -ENODEV;
	qmgr_regs = devm_ioremap_resource(dev, res);
	if (IS_ERR(qmgr_regs))
	return PTR_ERR(qmgr_regs);

	irq1 = platform_get_irq(pdev, 0);
	if (irq1 <= 0)
	return irq1 ? irq1 : -EINVAL;
	qmgr_irq_1 = irq1;
	irq2 = platform_get_irq(pdev, 1);
	if (irq2 <= 0)
	return irq2 ? irq2 : -EINVAL;
	qmgr_irq_2 = irq2;

	/* reset qmgr registers */
	for (i = 0; i < 4; i++) {
	__raw_writel(0x33333333, &qmgr_regs->stat1[i]);
	__raw_writel(0, &qmgr_regs->irqsrc[i]);
	}
	for (i = 0; i < 2; i++) {
	__raw_writel(0, &qmgr_regs->stat2[i]);
	__raw_writel(0xFFFFFFFF, &qmgr_regs->irqstat[i]); /* clear */
	__raw_writel(0, &qmgr_regs->irqen[i]);
	}

	__raw_writel(0xFFFFFFFF, &qmgr_regs->statne_h);
	__raw_writel(0, &qmgr_regs->statf_h);

	for (i = 0; i < QUEUES; i++)
	__raw_writel(0, &qmgr_regs->sram[i]);

	if (cpu_is_ixp42x_rev_a0()) {
	handler1 = qmgr_irq1_a0;
	handler2 = qmgr_irq2_a0;
	} else
	handler1 = handler2 = qmgr_irq;

	err = devm_request_irq(dev, irq1, handler1, 0, "IXP4xx Queue Manager",
	NULL);
	if (err) {
	dev_err(dev, "failed to request IRQ%i (%i)\n",
	irq1, err);
	return err;
	}

	err = devm_request_irq(dev, irq2, handler2, 0, "IXP4xx Queue Manager",
	NULL);
	if (err) {
	dev_err(dev, "failed to request IRQ%i (%i)\n",
	irq2, err);
	return err;
	}

	used_sram_bitmap[0] = 0xF; /* 4 first pages reserved for config */
	spin_lock_init(&qmgr_lock);

	dev_info(dev, "IXP4xx Queue Manager initialized.\n");
	return 0;
	}

	static int ixp4xx_qmgr_remove(struct platform_device *pdev)
	{
	synchronize_irq(qmgr_irq_1);
	synchronize_irq(qmgr_irq_2);
	return 0;
	}

	static const struct of_device_id ixp4xx_qmgr_of_match[] = {
	{
	.compatible = "intel,ixp4xx-ahb-queue-manager",
	},
	{},
	};

	static struct platform_driver ixp4xx_qmgr_driver = {
	.driver = {
	.name = "ixp4xx-qmgr",
	.of_match_table = of_match_ptr(ixp4xx_qmgr_of_match),
	},
	.probe = ixp4xx_qmgr_probe,
	.remove = ixp4xx_qmgr_remove,
	};
	module_platform_driver(ixp4xx_qmgr_driver);

	MODULE_LICENSE("GPL v2");
	MODULE_AUTHOR("Krzysztof Halasa");

	EXPORT_SYMBOL(qmgr_put_entry);
	EXPORT_SYMBOL(qmgr_get_entry);
	EXPORT_SYMBOL(qmgr_stat_empty);
	EXPORT_SYMBOL(qmgr_stat_below_low_watermark);
	EXPORT_SYMBOL(qmgr_stat_full);
	EXPORT_SYMBOL(qmgr_stat_overflow);
	EXPORT_SYMBOL(qmgr_set_irq);
	EXPORT_SYMBOL(qmgr_enable_irq);
	EXPORT_SYMBOL(qmgr_disable_irq);
	#if DEBUG_QMGR
	EXPORT_SYMBOL(qmgr_queue_descs);
	EXPORT_SYMBOL(qmgr_request_queue);
	#else
	EXPORT_SYMBOL(__qmgr_request_queue);
	#endif
	EXPORT_SYMBOL(qmgr_release_queue);